config: Add the foundation for GDPR privacy configuration

See #4616

config/configProvider.go

@@ -13,6 +13,12 @@
 
 package config
 
+import (
+	"strings"
+
+	"github.com/spf13/viper"
+)
+
 // Provider provides the configuration settings for Hugo.
 type Provider interface {
 	GetString(key string) string
@@ -25,3 +31,14 @@ type Provider interface {
 	Set(key string, value interface{})
 	IsSet(key string) bool
 }
+
+// FromConfigString creates a config from the given YAML, JSON or TOML config. This is useful in tests.
+func FromConfigString(config, configType string) (Provider, error) {
+	v := viper.New()
+	v.SetConfigType(configType)
+	if err := v.ReadConfig(strings.NewReader(config)); err != nil {
+		return nil, err
+	}
+	return v, nil
+
+}